This invention relates to electrical connectors and more particularly a connector part having a contact carrying recessed end face characterized by a projecting skirt which extends beyond the end face and where the skirt is provided with stiffening.
Molded electrical connectors having recessed end faces which may support either male or female contact components are known. A common purpose for the recessed end face is to allow a mating connector member to be inserted into the recess of the other connector member therefore providing environmental protection for the actual contact""s connection area. In order to enhance the environmental protection, the projecting skirt is molded of a flexible rubber or plastics material and has an inner diameter closely approximating the outer diameter of the cooperating connector portion to be inserted into the recess. In some instances there may in fact be a slight interference fit relying on the resiliency of the rubber or plastic to accommodate the inserted member.
Due to the nature of the molded rubber or plastic and to the desire to maintain a snug fit, such connectors have experienced fold-over of the open end of the skirt during insertion of the cooperating connector member. This fold-over can adversely affect the performance of the connector, both by making it difficult to make a secure connection, leading to incomplete insertion and by opening leakage paths. Additionally, the skirt end becomes susceptible to damage and tearing as a result of the fold-over.
It has been known to provide a stiffener circumferentially around the OD of the skirt adjacent the skirt""s open end to provide resistance to fold-over. Such stiffeners are normally formed as metal bands or the like and are normally held in place by adhesives. It has been known to provide outer diameter grooves in the skirt for receipt of the stiffener. Such adhesive attached stiffeners can, however, deteriorate, break loose, crack, and otherwise lose effectiveness. Where the electrical connectors are used in high power connections, it is strongly desired to have a circumferential stiffener which is permanently affixed to the connector skirt.
While it has been suggested to resolve these problems by molding a circumferential stiffener into the skirt at the time of formation, this solution, while enhancing the permanency of the attachment of the circumferential stiffener to the skirt, presents manufacturing difficulties. Large, high amperage plug sets are normally molded in high pressure molds which may consist of two hinged-together mold halves which, when closed, define an interior cavity space. Mold plugs, i.e. head and gripper bars, are provided to respectively close the opposite axial ends of the mold cavity and cooperate with the cavity features to define the configuration of parts of the to-be-molded plug component. For example, the skirt has its inner diameter formed by the outer diameter of an axially extending boss projecting into the mold cavity from the head bar. That boss, in turn, has bores into which the contacts are inserted to position them during molding. If the circumferential stiffener is to be molded into the skirt, it needs to be suspended in the mold at the time of closure of the mold halves. It has been suggested to suspend the stiffener by carrying the circumferential stiffener in the mold housing itself. This can be accomplished in a number of ways, such as, for example, by utilizing a T-shaped cross section stiffener with a part of the leg of the T received in a groove in the ID of the mold cavity thereby positioning the crossbar of the T interior of the space into which the skirt will be molded. While this and other approaches to positioning the circumferential stiffener in the mold cavity may be intended to properly position the stiffener in the open area of the mold cavity which will define the skirt, they make opening and closing the mold difficult. This presents another alignment problem during the movement of the mold halves from the open position to the closed position. Because these mold halves are heavy and awkward to properly position, molded in place circumferential stiffeners proposed thusfar present significant manufacturing challenges. In addition, because the connector components are retained in place during molding by a mold head bar, any positioning of a stiffener during molding by any mold part other than the head bar can result in a mispositioning of the stiffener relative to other components.
It would therefore be an advance in the art to provide a molded in-place circumferential stiffener for circumferential skirts of electrical connectors where the stiffener would not interfere with closure of the mold during manufacturing.
This invention avoids deficiencies in the prior art by having the circumferential stiffener carried in the mold cavity by the end plug or head bar. Preferably the head bar is provided with a plurality of projecting support fingers circumferentially positioned about the boss and extending coaxially with the boss from the head bar end wall. These fingers are arranged to have outer surfaces at approximately the position of the inner diameter of the cavity. Preferably the stiffener is carried on the radially inner faces of the fingers and will therefore be spaced from the inner diameter of the cavity by the thickness of the spacer-carrying portion of the fingers. This results in the stiffener being molded into the sleeve intermediate the inner and outer diameter of the sleeve, at a position spaced from the axial end of the sleeve determined by the length of the support end of the fingers. While substantially the entirety of the spacer will be imbedded within the sleeve, the presence of the spacer is detectable by the notches left in the sleeve OD by the fingers. Upon completion of the molding, the proper positioning of the stiffener can therefore be confirmed. Further, because the fingers leave notches which are open at the skirt axial end, the positioning of the stiffener can be confirmed even after the plug has been received in an attached housing. Thereafter if desired, the notches can be partially or fully filled in.
In an embodiment of the invention, at least three fingers are provided in the head bar, and the fingers individually are provided with undersurface ledges for properly positioning the stiffener.
In an embodiment of the invention the stiffener is formed as a spring thereby enhancing its ability to conform to changes within the sleeve.
In an embodiment the stiffener is formed as a wave spring.
In an embodiment the stiffener is formed as a coil.
In an embodiment the stiffener is a solid band.